Latitude by Local Apparent Noon (LAN), ContinuedNumerousSightsThe method of taking numerous sights is a modification of themaximum altitude method. It is useful under conditions where heavyseas, clouds, and the like may make steady observation impossible.Well before watch time of LAN, the observer begins taking a series ofaltitudes. Their number depends on the difficulties of the situation andthe possible error in computed time of transit. He/she reads off thealtitudes to a recording assistant, turning the tangent screw slightly aftereach observation to make sure that the next altitude is an independentsight. Observations are discontinued when the altitude definitely showssigns of decreasing.Under favorable conditions, even a series of skillfully taken observationsmay show an occasional erratic deviation from the normal gradual riseand fall. After sights showing a radical difference from the preceding orsucceeding series are discarded, however, the hang should becomeevident, and it should be possible to judge the maximum altitude. Thefigure selected will probably be less than the altitude shown in oneobservation and more than that below it. The result should give latitudewith an error no more than 1'. This reading is considerably moreaccurate than could be obtained by a single sight under the conditionsdescribed.FindingLatitudeAs you now know, you must first obtain a sight of the Sun when its atmaximum altitude and the time of observation. With this and a DRposition, we can reduce the sight to find latitude; now we can work thesecond part of our strip form.9-38